Géoazur, Unité Mixte de Recherche 6526, Institut de Recherche pour le Developpement, Port Vila, Vanuatu.
Proc Natl Acad Sci U S A. 2011 Aug 9;108(32):13019-22. doi: 10.1073/pnas.1102842108. Epub 2011 Jul 27.
Since the late 1990s, rising sea levels around the Torres Islands (north Vanuatu, southwest Pacific) have caused strong local and international concern. In 2002-2004, a village was displaced due to increasing sea incursions, and in 2005 a United Nations Environment Programme press release referred to the displaced village as perhaps the world's first climate change "refugees." We show here that vertical motions of the Torres Islands themselves dominate the apparent sea-level rise observed on the islands. From 1997 to 2009, the absolute sea level rose by 150 + /-20 mm. But GPS data reveal that the islands subsided by 117 + /-30 mm over the same time period, almost doubling the apparent gradual sea-level rise. Moreover, large earthquakes that occurred just before and after this period caused several hundreds of mm of sudden vertical motion, generating larger apparent sea-level changes than those observed during the entire intervening period. Our results show that vertical ground motions must be accounted for when evaluating sea-level change hazards in active tectonic regions. These data are needed to help communities and governments understand environmental changes and make the best decisions for their future.
自 20 世纪 90 年代末以来，托雷斯海峡群岛（瓦努阿图北部，西南太平洋）周围海平面上升引起了强烈的地方和国际关注。2002-2004 年，由于海平面不断上升，一个村庄被迫迁移，2005 年，联合国环境规划署的一份新闻稿称，这个被迫迁移的村庄可能是世界上第一批因气候变化而产生的“难民”。我们在这里表明，托雷斯群岛本身的垂直运动主导了在这些岛屿上观测到的海平面上升的表象。从 1997 年到 2009 年，绝对海平面上升了 150 + /-20 毫米。但是 GPS 数据显示，在同一时期，岛屿下沉了 117 + /-30 毫米，几乎使海平面上升的表象翻倍。此外，在此期间前后发生的几次大地震导致了数百毫米的突发性垂直运动，产生了比整个间隔期间观测到的更大的海平面变化表象。我们的研究结果表明，在评估活动构造区域的海平面变化危害时，必须考虑垂直地面运动。这些数据有助于社区和政府了解环境变化，并为他们的未来做出最佳决策。
